The present invention relates to a method for loading 35 mm photographic roll film into a film cartridge, and to an apparatus for practicing such a method. More specifically, the invention relates to such a method and apparatus in which, while the caps, spool and shell plate (which are the essential components of a film cartridge) are supplied to form a film cartridge, film is simultaneously loaded into the same film cartridge.
An example of a conventional method for loading a film in a cartridge is a film intermittent loading method employing a turntable system used in a film loading apparatus such as that disclosed in U.S. Pat. No. 2,940,232. In accordance with that method, a turntable rotating intermittently is used. A station for supplying the spool, caps and shell plate, a film winding station for winding film on a spool, and a capping station for inserting the spool on which the film has been wound into the cylindrical structure formed by the shell plate and fitting the caps on both ends of the cylinder are provided above the turntable. The work is stopped at each station temporarily so that the above-described manufacturing operations can be carried out.
In accordance with this method, the period of time for which the turntable is stopped at each station during the assembly of film cartridges is fixed. Accordingly, the total assembly time per cartridge is fixed. Therefore, it is difficult to increase the speed of rotation of the turntable. Thus, it is difficult to manufacture film cartridges on a large scale at a high speed using the conventional method.
U.S. Pat. No. 3,586,258 discloses a device in which photographic film is inserted into an assembled film cartridge through a slot in the cartridge and wound onto the spool of the cartridge. In practicing this method, the winding time limits the assembly operation, and accordingly it is impossible to increase the manufacturing rate. In addition, insertion of the film into the film cartridge longitudinally through the slot in the cartridge requires a mechanism having a high positioning accuracy and is time consuming.
U.S. Pat. No. 4,115,913, filed by the present applicant, discloses a film loading method in which the caps, spool and shell plate are mounted on the same axis. While these components are being conveyed, the film is wound on the spool. Thereafter, the film cartridge is assembled. With this method, the film can be wound on the spool at a high speed, that is, it can be loaded into the cartridge at a high speed. Therefore, film cartridges can be produced on a large scale.
However, the method is nevertheless disadvantageous in the following points: Since the film is loaded while the above-described components are being conveyed, the film supplying system is intricate, and it is difficult to connect the film to the spool with a high reliability. Furthermore, the film winding and loading head must be capable of shaping the shell plate, supplying the caps, and transmitting power, in addition to its own function. Therefore, the apparatus is necessarily bulky and complex. In addition, the head conveying speed is limited, and accordingly the speed of winding and loading film is limited.
Accordingly, an object of the invention is to provide a film loading method in which the above-described difficulties accompanying a conventional film loading method have been eliminated, and the film can be wound and loaded into a cartridge at a high speed with a high reliability. It is also an object of the invention to provide an apparatus for practicing this method.